IntelliJ IDEA 2016.1 Help

XPath Expression Evaluation

Evaluating XPath expressions in IntelliJ IDEA has two main purposes: Testing XPath expressions that are to be used in program
code or XSLT scripts, and making structured queries against XML documents.
The Evaluate XPath action can be invoked either from the editor context menu,
the main Search Menu or the main toolbar by clicking the action's icon .

The Expression Evaluation has two different modes, a simple mode, that allows you
to enter simple one-line expressions and doesn't allow you to configure and Context settings. For more convenient
editing of long expressions in a multi-line style way, there's the advanced mode dialog that also has a button to
edit some context settings, such as namespaces and their prefixes, and variables to use for the evaluation.

Both dialogs feature a history of the recently evaluated expressions, completion, syntax-checking and highlighting,
as well as some semantic error checking of the entered expression. Semantic checks include validation of used
namespace prefixes, useless XPath expressions (e.g. @comment()) and node tests for element/attribute
names that don't occur in the context document and would not be successfully matched.

Some error checks and XPath inspections also provide Quick Fixes for detected problems, e.g. the possibility to map
an unresolved namespace-prefix to a URI by intention.

Simple Mode

The simple mode comes with an input field that can be used to enter simple one-line expressions that don't require
any customization of namespace prefixes or make use of predefined variables. The last recently used expressions can
be selected from the drop-down list.

Advanced Mode

The advanced mode adds the possibility to edit expressions in a multiline editor and has another button to edit the
XPath Context. The expression history can be browsed by the Up- and Down arrays on the
right of the dialog or the keyboard shortcuts for the previous/next history element (usually Ctrl-Alt-Up, Ctrl-Alt-Down).

XPath Context

This dialog allows you to assign custom prefixes to the namespace URIs that are used in the context document. This can
be useful to assign a shorter prefix, resolve prefix clashes or to actually define a prefix for the default
namespace. This can be essential because XPath does not automatically match elements in the default namespace
without specifying a prefix for the element to be matched.

The XPath Context also includes the possibility to define custom XPath variables that can be used in queries for
repeating expressions. Each variable in the table can be assigned an expression that will be evaluated once when the
query is executed. The resulting value is then available for multiple use at no additional computational cost.

Options

Highlight results

This highlights the matched nodes in the current editor. Matched nodes that don't belong to the current editor (may
happen by using the document() function) are not highlighted. It's recommended to display such
cross-document results in the Find Usages toolwindow.

Show results in Usage View

Shows all matched nodes in the Find Usages toolwindow.
Check Open in new tab to open the result in a new tab instead of reusing the last one.